a female aedes mosquito. File PhotoThe children who are older than six years are at a greater risk of dengue infection since they spend more time in crowded places like schools and parks, says a new study of icddr,b.Under the study, two household serosurveys were conducted in 2012 to assess the seroprevalence and seroincidence of dengue fever virus (DENV).During the period, information on demographic, socioeconomic, and other relevant characteristics was collected from the study participants using a structured socioeconomic questionnaire. The findings have been released recently.The study combines serological surveys of blood samples with participant interviews to determine various socio-cultural risk factors that predict DENV infection.Serological surveys measure the presence of circulating antibodies in blood samples to objectively determine whether each participant has been infected with DENV in the past.The study identifies various household and community level risk factors that increase the risk of dengue infection. At the household level, the presence of ornamental potted plants, potential breeding grounds for mosquitoes was found to increase the risk for DENV infection.According to research investigator at icddr,b and co-author of the study Kishor Kumar Paul, home-based interventions such as removing indoor potted plants and increased bed net use, as well as vector control measures in public parks, will reduce the exposure to dengue infections among the city dwellers.Dengue is spread by mosquitoes Aedes aegypti and Aedes albopictus, the two species which can also transmit other mosquito-borne viruses.Multiple dengue outbreaks have occurred in Bangladesh since the first major outbreak in 2000. The vast majority (91 pc) of reported dengue cases between 2000 and 2009 occurred in Dhaka.Official data show that so far over 660 dengue cases with two fatalities have been reported this year in the capital. Of them, 121 dengue cases were reported in May, followed by 202 in June and 84 up to 16 July 2017.The new study found a very high degree of seroprevalence for DENV across Dhaka city, with the highest seroprevalence in the older, more densely populated areas. It is an indicator of significant unreported dengue virus-associated illness.There are also many new infections that occur between the pre- and post-monsoon period, suggesting that DENV was circulating through the city quite intensely during the study.Findings of this study indicate that home-based interventions like removing indoor potted plants and increased bed net use, in addition to vector control measures in public parks, would reduce exposure to DENV and further decrease risk of viral associated disease.Principal investigator of the study W Abdullah Brooks said this study demonstrates that formulation of an active DENV surveillance system is urgently warranted, particularly to estimate the impact of DENV disease burden in Dhaka and other urban areas of the country.